01 - In a large skillet over medium heat, crumble and cook the breakfast sausage until browned and cooked through, about 6 to 8 minutes. Transfer the sausage to a plate and set aside.
02 - In the same skillet, sauté the bell pepper and onion until softened, about 4 to 5 minutes. Add the chopped spinach and cook until wilted, about 1 minute.
03 - In a mixing bowl, whisk together the eggs, milk, salt, and pepper. Pour the egg mixture into the skillet with the vegetables. Scramble gently over medium-low heat until the eggs are just set. Remove from heat and stir in the cooked sausage.
04 - Lay the tortillas on a flat surface. Evenly divide the egg mixture among the tortillas and top each portion with shredded cheddar cheese.
05 - Fold in the sides of each tortilla and roll up tightly to form secure burritos. Allow to cool slightly, then wrap each burrito individually in foil or parchment paper. Place in a freezer-safe bag or container.
06 - From frozen, remove the foil, wrap in a paper towel, and microwave on high for 2 to 3 minutes. Alternatively, bake at 350°F for 25 to 30 minutes until heated throughout.